Internal combustion engine

ABSTRACT

AN IMPROVED INTERNAL COMBUSTION ENGINE CONSISTS OF A UNITARY CRANK CASE HAVING A CAVITY CAST AT THE MIDDLE OF ITS LENGTH TO HOUSE THE TIMING DRIVE AND A DRIVE TO AUXILIARY EQUIPMENT. THE CAVITY HAS OPENINGS AND THE AUXILIARY EQUIPMENT IS MOUNTED ON LOAD BEARING COVERS WHICH CLOSE THESE OPENINGS.

March 6, 1973 w. F. STEWART 3,719,173

INTERNAL COMBUSTION ENGINE Filed NOV. 10, 1971 5 Sheets-Sheet l Inventor WILLIAM F. STEWART B MA March 6, 1973 w. F. STEWART INTERNAL COMBUSTION ENGINE S Sheets-Sheet 2 Filed Nov. 10. 1971 3 3w 8 E i W lnvenlor WILLIAM F. STEWART B 4 Maui-k Attorneys 5 Sheets-Sheet I Filed Nov. 10, 1971 m w n t FAWN 4W w E l A v 5 m F March 6, 1973 w. F. STEWART 3,719,178

INTERNAL COMBUSTION ENGINE I Filed Nov. 10. 1971 5 Sheets-Sheet 4 lnvenlo WILLIAM F. STEWART B wi March 6, 1973 H w. F. STEWART 3,719,178

INTERNAL COMBUSTION ENGINE Filed Nov. 10, 1971 5 Sheets-Sheet l FIG 5 x LU 48 45 Inventor WILLIA M F. STEWAQT y Y wfkwm United States Patent 3,719,178 INTERNAL COMBUSTION ENGINE William F. Stewart, Peterborough, England, assignor to Perkins Engines Limited, London, England Filed Nov. 10, 1971, Ser. No. 197,429 Claims priority, application Great Britain, Nov. 10, 1970, 53,522/70 Int. Cl. F021? 7/00 US. Cl. 123-195 A 12 Claims ABSTRACT OF THE DISCLOSURE An improved internal combustion engine consists of a unitary crank case having a cavity cast at the middle of its length to house the timing drive and a drive to auxiliary equipment. The cavity has openings and the auxiliary equipment is mounted on load bearing covers which close these openings.

This invention relates to engines having a plurality of cylinders each housing a reciprocable piston. Such engines will hereinafter and in the appended claims be referred to as reciprocating engines. In particular the invention relates to internal combustion reciprocating engines which are liquid cooled.

'It has been known to provide a multicylinder engine in which the timing drive gears are located at the centre of the length of the engine. In some cases these gears have been worm and wheel gears driving a jackshaft which in turn drives a camshaft and/or electrical distributor. In other cases the gears have been spur gears mounted in a cavity formed by the two halves of a two piece crankcase of an air cooled engine.

It is an object of this invention to provide a multicylinder engine in which the timing drive is located between cylinders in a unitary crankcase. A further object of the invention is to provide a drive from between the cylinders to auxiliary apparatus mounted externally of the crankcase. Yet a further object of the invention is to make provision for easy driving attachment of a range of auxiliary equipment.

In accordance with these objects, this invention consists of a reciprocating engine comprising a crankcase defining a timing gear cavity located between adjacent cylinders thereof, a crankshaft and a camshaft supported by the crankcase, crankshaft and camshaft timing wheels mounted on their respective shafts and drivingly connected with each other at least partially Within said cavity, wherein said cavity is open on at least one side of the crankcase and the cavity opening is closed by a load bearing cover member on which is supported at least one auxiliary device drive wheel which is drivably connected to the crankshaft and to an auxiliary device.

Preferably said auxiliary device is driven from the crankshaft through an intermediary drive member. The intermediary drive member may be constituted by the camshaft timing wheel or by a further wheel mounted on the cover member.

Preferably also, the wheels comprise gearwheel and in the case a V-engine the opening can occur at the top side between the cylinder banks. Also the cover can 'be arranged so that a driven wheel drives two auxiliary devices. Provision is made to drive auxiliary devices on two spaced axes passing through each cover.

Further objects and features of this invention will become more readily apparent upon reference to the following detailed description of the attached drawings wherein:

FIG. 1 is one side elevation of an engine according to the invention partially sectioned at one place on the line II in FIG. 3;

FIG. 2 is the opposite side elevation of the engine of FIG. 1 section on the line IIII in FIG. 3;

'FIG. 3 is a cross sectional view on the line III-III of FIG. 1;

FIG. 4 is a partial sectional view on the line IV--IV of FIG. 3;

FIG. 5 is a partial sectional view on the line V-V in FIG. 3;

FIG. 6 is a partial sectional view on the line VI-VI in FIG. 3.

Referring now to FIGS. 1, 2 and 3, an engine 10 consists of a monoblock crankcase containing six cylinders 12 in line and adapted, by the provision of cooling passages 14 around the cylinders 12, to be cooled by a liquid. The cylinders 12 are not shown in detail but their centre lines are shown numbered in the conventional manner from 1 to 6 from the front of the engine. In this case, the front of the engine is defined as the end which carries the fan. The spacing between the cylinders 3 and 4 is larger than that between other adjacent cylinders so as to accommodate a cavity 16 cast into the crankcase, which cavity 16 contains the timing gears for the engine. The cavity 16 is defined by walls 18, 20, 22, 24 and 26, as seen in FIG. 3 and by walls 28 as seen in FIGS. 4, 5 and 6. The wall 18 separates the cavity 16 from a longitudinal coolant gallery 30. The walls 20, 22 and 24 separate the cavity 16 from the general coolant passages 14 surrounding the cylinders 12. The wall 26 is part of a center main bearing support rib 34 which is buttressed from a crankcase skirt 36.

The walls 26 and 28, and 18 and 28, merge as seen in FIG. 4.

In FIG. 5 the wall 28 separates the cavity 16 from the interiors of cylinders 3 and 4 and, lower down, from the crankcase space 36. The walls 28 merge into the upper center main bearing support 38 which is split to accommodate a crankshaft gearwheel 40 secured to the crankshaft 42, for example by electron beam welding, at the center of the center main bearing journal 44. The center main bearing cap 46 is recessed at 48 to accommodate the gearwheel 40.

FIG. 4 shows a two-part camshaft 50, one part having a flange 52 and the other a spigot 54 protruding from a bearing 56. The flange 52 fits into a recess 58 in a cam gearwheel 60 and screws 62 hold the flanges 52, gearwheel 60 and bearing 56 together for mutual rotation.

As seen in FIG. 3 the crankshaft gearwheel 40 meshes with cam gearwheel 60 and with an idler gearwheel 64.

The cavity 16 opens on the left hand side of the engine, with respect to FIG. 3, and the opening is closed by a load bearing cover member 66 which is bolted to the crankcase around a peripheral flange, as seen in FIGS. 2 and 3. As seen in FIG. 3 the cover member 66 is ear shaped and has two apertures in each of two laterally extending walls 70 and 72, FIG. 2. The apertures in the rear lateral wall 70 are at 74 and 76 and are both flanged and provided with threaded holes to receive fastening screws. Only the center line 78 of the screw is shown on the accompanying drawings-both the screw and the screw holes are left out of all aperture cover members for the sake of clarity. A flange 80 of an auxiliary device in the form of a hydraulic pump 82 butts against the flanged Wall 70 of the cover 16 and an outrigger 84 supports a bearing for one trunnion of an auxiliary device drive gearwheel 86. The other trunnion is supported directly on a bearing 88 set in the wall 72. A splined shaft 83 of the pump 82 engages internal splines on the gearwheel 86. The bearing 88 is covered by a plate 90.

The lower aperture 76 in the wall 70 is closed by a plate 94 which carries a bearing 96 in which is supported one trunnion of a second auxiliary device drive gearwheel 98. The other trunnion of the gearwheel 98 is carried on a bearing 100 directly in the flanged wall 72. An auxiliary 3 device in the form of a water pump 102 is fastened to the wall 72 by screws, not shown, and its shaft 103 makes driving engagement with the gearwheel 98' by means of a square and entering a square hole 104.

Both gearwheel 86 and 98 engage and are driven by the crankshaft through the crankshaft gearwheel 40 and an intermediary drive member in the form of the cam gearwheel 60.

The mounting of gearwheels on the cover member 66 is exemplary in that a gearwheel can be mounted in part by an auxiliary device and in part by the cover member 66 itself. Also, it is clear that by removing the cover 90 and substituting a further auxiliary device, the gearwheel 86 could drive both the hydraulic pump 82 and the new device. Similarly, the gearwheel 98 could drive an additional device, provided it had an outrigger bearing incorporated in it, or as an adaptor, which would be substituted in place of the plate 94. Thus, the cover member 66 would be capable of mounting four auxiliary devices to be driven by two gearwheels.

Turning now to the right hand side, with respect to FIG. 3 of the engine, which is shown in FIGS. 1 and 2, the cavity 16 opens to that side also and a second cover member 106 is provided. The cover 106 carries three gearwheels, namely an auxiliary device in the form of an injection pump 110, the idler gearwheel 64 and an auxiliary device drive gearwheel 112. The idler gearwheel 64 forms an intermediary drive member and is mounted, as best seen in FIG. 6 on a pedestal 114 fastened to the attachment flanges 116 of the cover member 106.

As distinct from the gearwheels 86 and 98 on the opposite side of the engine it will be seen that the gearwheels 108 and 112 are carried in quite a different manner. The pump 110 is supported by the cover member 106 on its mounting flange 118, FIG. 1, by screws, not shown, and

is located very accurately in a circular aperture 120 by a spigot 122. Likewise an auxiliary device in the form of a compressor 124 is carried by a spigot 126 in an aperture 128 and is held fast to the cover by screws through a flange 130. During manufacture, the apertures 120 and 128' are bored at the same time and on the same jig fixture. Thus, the shafts 132 and 134 of the injection pump 110, and the compressor 124 are axially aligned within very close tolerances and the gearwheel 108 is sandwiched between two flanges 136 and 138 which are through-fastened together by screws 140. The flange 136 is fastened to the shaft 132 either integrally or by a key or the like. The flange 138 IS splined internally to receive the splined shaft 134. Thus, the gearwheel 108 is not carried directly by the cover member 106 at all.

An auxiliary device in the form of steering pump 142, which is a small hydraulic pump, is flange mounted on the cover member 106 and spigotted through an aperture 144, and carries the gearwheel 112 cantilever mounted on its shaft 146. No support is required from the opposite wall designated at 148 and an aperture 150 in the wall is covered by a plate 152.

Clearly, the number of auxiliary drives which may be accommodated on the engine described above is eight. Other auxiliary devices which may be needed in other installations are an electric generator, an exhauster or vacuum pump for the vehicle brakes, a supercharging compressor, and any other power-take-off even though it may require a drive through a universally jointed shaft or flexible shaft to a location remote from the engine. A tachomter drive may also be easily accommodated.

There are numerous advantages in the above arrangement, for example, both ends of the engine are unencumbered by the presence of timing gears and hence provision can be made for assembling the fan and alternator drives on either end. The fan 154 and the alternator 156 are driven by a pulley and a V-belt 158 from the crankshaft. Furthermore, the starter motor can be assembled on either side of the engine as shown at 160 in FIG. 1 and at 162 in FIG. 2. The presence of the cavity in the crankcase enables two cylinder heads to be used, the advantage being mainly that the smaller cylinder head can be made more easily and is less prone to thermal distortion. Further, the presence of the cavity can be turned to advantage in that coolant can be fed into the coolant gallery 30' at the mid-point of the engine thus leading to more uniform cooling of the cylinders than if the coolant were fed in at one end. Also, the coolant can be drawn off at this point.

Some of the other advantages that result from the present invention are as follows. At least some of the noise generated by the timing gears will be generated within the engine block and the stiff surrounding engine structure will reduce the propagation of such noise. Noise generated by meshing of gears will tend to be radiated from the covers but these are easily adaptable to detail designing aimed expressly at reducing their noise radiation and are easily covered with sound absorbing material. The multiplicity of auxiliary devices that can be driven without changing the basic engine structure and simply by changing the devices on the covers, or by changing the covers only, is extremely advantageous when engines are to be supplied for a multiplicity of different applications.

While the invention has been described above with reference to an embodiment utilising gearwheels, clearly any other form of drive transmission means could be utilized e.g. friction drive wheels, worm gears, friction belts and pulleys. However, for convenience in the appended claims the term wheels has been utilized to define all such drive transmission means.

The embodiment described above relates to reciprocating engine in which the cylinders are arranged in a single bank clearly the invention is equally applicable to multibank engines such as, for example, those having their cylinders arranged in a V-formation. In such a case the cavity 16 is preferably arranged so that it opens into the top side of the engine, that is, in the angle between the banks of cylinders.

I claim:

1. A reciprocating engine comprising a crankcase defining a timing gear cavity located between adjacent cylinders thereof, a crankshaft and a camshaft supported by the crankcase, crankshaft and camshaft timing wheels mounted on their respective shafts and drivingly connected with each other at least partially within said cavity, wherein said cavity is open on at least one side of the crankcase and the cavity opening is closed by a load bearing cover member on which is supported at least one auxiliary device drive wheel which is drivably connected to the crankshaft and to an auxiliary device.

2. An engine according to claim 1, wherein said auxiliary device is driven from the crankshaft through an intermediary drive member.

3. An engine according to claim 2, wherein said intermediary drive member is constituted by said camshaft timing wheel.

4. An engine according to claim 2, wherein said intermediary drive member is constituted by a further wheel mounted on said cover member.

5. An engine according to claim 1, wherein the auxiliary device drive wheel is supported on the cover by the auxiliary device being directly supported by the cover member.

6. An engine according to claim 5, wherein said auxiliary device drive wheel is drivably connected with the camshaft timing wheel.

7. An engine according to claim 6 wherein a further auxiliary device drive wheel is provided which is in mesh with the camshaft timing wheel, is supported on the cover member and drives a further auxiliary device.

8. An engine according to claim 1, wherein the cylinders thereof are arranged in a V-formation and said cavity opens into the top side of the engine, that is in the angle between the banks of cylinders.

9. An engine according to claim 1 wherein the cylinders thereof are arranged in a single bank and said cavity opens on both lateral sides of the engine and both openings are closed by load bearing cover members on each of which is supported at least one auxiliary device each drivable by an auxiliary device drive wheel supported within the pertinent cover member.

10. An engine according to claim 1, wherein at least one of the auxiliary device drive wheels supported by one said cover member drives two auxiliary devices supported on said cover members.

11. An engine according to claim 1 wherein the cavity is located approximately at the mid-point of the length of the engine and in which said cylinders are arranged in banks, each bank of cylinders being provided with two cylinder heads.

12. An engine according to claim 1, wherein said crankshaft gear is secured to the crankshaft by electron beam welding.

References Cited UNITED STATES PATENTS 2,157,761 5/1939 Kishline 123--195 AX 2,363,804 11/1944 Reiland ..7 123195 AX 3,422,806 1/ 1969 De Lorean 123-195 C 10 3,673,990 7/1972 Alfieri 123-195 AX AL LAWRENCE SMITH, Primary Examiner 

